Collaborative Research: CMG: Magnetohydrodynamics (MHD) Turbulence and the Geo-Dynamo: Lagrangian Averaging and Direct Numerical Simulations (DNS)

合作研究：CMG：磁流体动力学 (MHD) 湍流和地球发电机：拉格朗日平均和直接数值模拟 (DNS)

• 批准号: 0327533
• 负责人: David Montgomery
• 金额: $ 10.47万
• 依托单位: Dartmouth College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0327533&HistoricalAwards=false
• 关键词: Collaborative; Research; CMG; Magnetohydrodynamics; MHD

Magnetic fields are a conspicuous feature of the ionospheres and magnetospheres of planets, including Earth, though their origin (the dynamo problem) is not well understood. This project is a theoretical investigation of magnetohydrodynamic (MHD) turbulence, or turbulent flow in the presence of magnetic fields. High resolution numerical simulations will be employed, and will be used to evaluate a method of simplifying turbulence processes called the Lagrangian-averaged (or "alpha") model. When validated, the method will be applied to MHD regimes relevant to the geodynamo (so-called low magnetic Prandtl number regimes) that have not been modeled previously. The work will not only advance the understanding of the geodynamo but will be a test of the alpha model, which has been proposed for other investigations of turbulent flow. The project provides for training graduate students and a postdoctoral research associate, and will sponsor an international workshop at NCAR on the modeling of complex geophysical flows in the summer of 2006. The grant is funded jointly by the Division of Atmospheric Sciences and the Division of Mathematical Sciences through the NSF program, Collaborations in Mathematical Geosciences (CMG).

磁场是包括地球在内的行星的电离层和磁层的一个显著特征，尽管它们的起源（发电机问题）还没有得到很好的理解。 本计画是对磁流体动力学（MHD）紊流或磁场中紊流的理论研究。 将采用高分辨率数值模拟，并将用于评估一种简化湍流过程的方法，称为拉格朗日平均（或“阿尔法”）模型。 验证后，该方法将适用于磁流体政权有关的geodynamo（所谓的低磁普朗特数制度），以前没有建模。 这项工作不仅将推进对地球发电机的理解，而且将是对阿尔法模型的测试，该模型已被提议用于湍流的其他研究。 该项目为研究生和博士后研究助理提供培训，并将于2006年夏天在NCAR主办一次关于复杂地球物理流建模的国际研讨会。 该赠款由大气科学部和数学科学部通过NSF计划数学地球科学合作（CMG）共同资助。